الفهرس 
Whey definition and importance
Economical restrictionOnly 14 pages are availabe for public view
 |  | from | 123 |  |  |
| | | from | 123 | | |
Abstract
Lactose hydrolysis and production of ethanol as a biofuel was
evaluated and conducted in the present study. Lactose was hydrolyzed by
Candida pseudotropicalis and Kluyveromyces fragilis that grown in whey
and synthetic medium. In addition, optimum pH and optimum incubation
temperature for lactose hydrolysis were studied and were found 3 and
37ºC respectively in Candida pseudotropicalis, while it were 5.1and 35ºC
respectively in Kluyveromyces fragilis. On the other hand, two isolates
and one strain of Saccharomyces cerevisiae were tested to produce
ethanol from hydrolyzed whey. The current study shows that the strain
was more effecciency in bioethanol production with level reached to
1.21% (v/v). Moreover, protoplast fusion was done between lactose
fermenting Candida pseudotropicalis and lactose nonfermenting
Saccharomyces cerevicae and the fusion process gave rise to new hybrid
yeast. The recombinants showed growth on lactose in whey and synthetic
medium. (The ethanol yields by some recombinants were reached 3.27%,
2.24%, 2.10% and 2.06% from whey medium and 2.54%, 2.00%, 1.88%
and 1.65% in synthetic media). Also the conversion of glucose that
released from lactose hydrolysis by Candida pseudotropicalis into
fructose via addition of immobilized glucose isomerase has been carried
out and fructose content was 65.21 mg/100ml. In addition antimicrobial
activities of whey proteins against the tested microorganisms (E. coli,
Staphylococcus aureus & Listeria monocytogenes) were assayed by
evaluating the inhibition zones diameters. The highest inhibition zone was
recorded for E. coli (10mm) followed by Staphylococcus aureus(9mm)
while there was no detectable effect on Listeria monocytogenes.
Keywords: Bioethanol, Fructose syrup, Galactose, Glucose isomerase,
Lactose, Protoplast fusion, Whey, Whey antimicrobial
activities, Candida pseudotropicalis, Kluyveromyces
fragilis, Saccharomyces cerevicae.